Many
people have either seen or know someone with a condition dubbed lazy
eye, cited as the most common visual impairment in children. The
lazy, or amblyopic, eye is often healthy but circuits within the brain
will favor processing things the child sees from just one of two eyes.
If left untreated, this condition can affect a person’s ability to
perceive depth. The result is stereo blindness. When both eyes are not
wired to work together, life is viewed in two dimensions instead of the
normal three most people can see.

Prakash Kara, Ph.D., Neurosciences assistant professor in the Darby
Children’s Research Institute, and his colleagues discovered a
functional map inside the brain using a new high-resolution laser
imaging technology. Published in Nature (advanced online publication,
Jan. 21), their work suggests how numerous brain cells related to 3-D
vision work together to process and understand what is seen through
both eyes at any given time.

“This study could have profound implications for our understanding of
what might be happening in the brain in certain conditions such as
neural blindness, where the eyes are fine, but the brain is not,” Kara
said. “I am optimistic that what we’ve discovered will eventually
contribute to the development of new behavioral training and
pharmacological therapies for restoring function to the compromised
brain circuits in various vision disorders that affect children.”

Supported by a grant from the National Eye Institute, Kara and his
colleagues discovered that the brain cells related to seeing the
environment in 3-D through both eyes are not scattered across the brain
randomly. Instead, the cells are organized in a precise functional map,
which optimally aligns itself with other visual maps in the brain. The
unique arrangement of these maps in a normal, healthy brain serves as a
benchmark for tracking changes in the wiring of circuits within the
brain of children with various vision disorders, such as lazy eye.
Consequently, Kara’s work will now focus on how the discovered
functional maps inside the brain that direct normal vision are affected
in specific types of lazy eye.

Friday, Feb. 6, 2009

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